Conventional automotive serpentine (V-ribbed) belt-driven front-end accessory drives consist of a driver pulley at an engine crankshaft, one or more driven pulleys at various accessories, and a spring-loaded single-arm or dual-arm pivoted tensioner pulley(s), usually located at least in the slack span of the driver/crankshaft pulley. The engine is started with a starter that engages and starts the engine, and then disengages once its started. One of the accessories may be an alternator/generator for supplying electrical power to the vehicle. In this configuration, a slack span of a driven/crankshaft pulley is the optimal location for the spring-loaded tensioner pulley(s) because the tension in that span may not be reduced by the span tensioning differences cause by the accessory pulley loads. In fact, the tension may be increased by the span tensioning differences caused by the accessory pulley loads.
It is known in the art to provide a tensioner for an endless power transmission belt that is driven by a crankshaft, where the belt is employed in driving a sheave comprising at least one accessory, which upon being driven creates a slack side and a tight side in the belt on opposite sides of the sheave and the tensioner comprises a first and second support arm, each respectively having pivot means, first and second idler pulleys carried by the first and second support arms, respectively, and a pivot pin extending through the pivot means and pivotally supporting the arms adjacent opposite sides of the sheave with the first pulley engaging the slack side and the second pulley engaging the tight side to enable tensioning thereof and in a similar manner as disclosed in U.S. Pat. No. 4,416,647. This reference is hereby incorporated herein by reference.
One aspect may be to provide an improved tensioner and positioning of a tensioner for an endless power transmission belt in an engine utilizing an AGS as the driving device.
Another aspect may be to provide an improved tensioner that also provides dampening of the belt, and thereby assures smooth running thereof free of vibration and/or oscillation.